Abstract

Transport measurements at cryogenic temperatures through a few-electron top gated quantum dot fabricated in a silicon/silicon-germanium heterostructure are reported. Variations in gate voltage induce a transition from an isolated dot toward a dot strongly coupled to the leads. In addition to Coulomb blockade, when the dot is strongly coupled to the leads, the authors observe the appearance of a zero bias conductance peak due to the Kondo effect. The Kondo peak splits in a magnetic field, and the splitting scales linearly with the applied field. They also observe a transition from pure Coulomb blockade to peaks with a Fano line shape.

Received 25 September 2006Accepted 11 December 2006Published online 16 January 2007

Acknowledgments:

The authors acknowledge helpful discussions with M. Eto, R. Joynt, M. Friesen, S. N. Coppersmith, and K. A. Slinker, and experimental assistance from L. M. McGuire. This work was supported in part by the NSA and LPS under ARO Contract No. W911NF-04-1-0389, and by the NSF under Grant No. DMR-0325634.